The primary screening variables are PEG, ion type, ionic strength, and pH. More than 60% of the published crystallizations utilized PEG as a primary crystallization reagent and in approximately 50% of those reports, the PEG was combined with an ion as a secondary crystallization reagent. PEG/Ion reagents are formulated without a buffer and are not pH titrated.

PEG/Ion 2 is an extension to the fundamental crystallization strategy in PEG/Ion. PEG/Ion 2 reagents cover the monodisperse, high purity Polyethylene glycol 3,350 and an array of neutralized and pH adjusted organic acids, multivalent ions, a novel Citrate BIS-TRIS propane buffer system and pH (4 – 8.8). The formulation of PEG/Ion 2 was developed at Hampton Research. Each of the 48 reagents in PEG/Ion 2 contains PEG 3,350 as the polymer (precipitant). The concentration of PEG is varied from 12% w/v to 20% w/v depending upon the type and concentration of buffer/salt paired with the polymer. Thirteen of the forty-eight PEG/Ion 2 reagents contain a separate buffer component. The remaining PEG/Ion 2 reagents are buffered by the titrated organic acid salt. Six of these thirteen conditions feature a novel Citric acid BIS-TRIS propane (CBTP) buffer. The CBTP buffer uses Citric acid and BIS-TRIS propane as the acid base pair to create a two component buffer system effective across pH 2.5 to 9.5. The ratio of Citric acid to BIS-TRIS propane determines the solution pH. Thirty-five of the forty-eight PEG/Ion 2 reagents contain a neutralized or pH adjusted organic acid in the presence of the polymer. Neutralized organic acids are highly effective crystallization salts.¹ Four PEG/Ion 2 reagents feature polyvalent cations. Two of these reagents contain cation mixes, saving sample by screening six different cations with only two reagents. Tryptone, a casein digest combinatorial library of peptides, is included in PEG/Ion 2. PEG/Ion 2 reagents 1-30, 42, 45-47 are formulated without a buffer and are not pH titrated.

PEG/Ion contains 48 unique reagents, 10 ml each.

PEG/Ion 2 contains 48 unique reagents, 10 ml each.

PEG/Ion HT contains 1 ml of each reagent from PEG/Ion and PEG/Ion 2 in a single Deep Well block format.

Ready-to-use reagents are sterile filtered and formulated with ultra-pure Type 1 water, using the highest purity salts, polymers, organics and buffers. Individual reagents are available through the Hampton Research Custom Shop.

应用
生物大分子的一级或二级、聚合物、盐和pH基质结晶筛选
特征
在汉普顿研究中心开发
PEG/Ion 是在 pH 4.5 – 9.2 存在单分散聚乙二醇 3,350 的情况下阴离子和阳离子的稀疏基质分布
PEG/Ion 2 在单分散 PEG 3,350 存在下筛选不同 pH 值 (3.7 – 8.8) 下滴定有机酸的完整曲线
PEG/Ion HT 在单个 96 Deep Well 模块中结合了 PEG/Ion 和 PEG/Ion 2
描述
Hampton Research 开发的 PEG/Ion 是一种结晶筛选，旨在评估单分散、高纯度的聚乙二醇 3,350 和 48 种独特的盐，这些盐代表了生物大分子结晶中常用的非常完整的阴离子和阳离子范围。主要筛选变量是 PEG、离子类型、离子强度和 pH 值。超过 60% 的已发表结晶使用 PEG 作为主要结晶试剂，并且在大约 50% 的报告中，PEG 与离子结合作为二级结晶试剂。 PEG/Ion 试剂是在没有缓冲液的情况下配制的，并且没有经过 pH 滴定。

PEG/Ion 2 是 PEG/Ion 基本结晶策略的扩展。 PEG/Ion 2 试剂涵盖单分散、高纯度聚乙二醇 3,350 和一系列中和和 pH 调节的有机酸、多价离子、新型柠檬酸盐 BIS-TRIS 丙烷缓冲系统和 pH (4 – 8.8)。 PEG/Ion 2 的配方是在 Hampton Research 开发的。 PEG/Ion 2 中的 48 种试剂中的每一种都包含 PEG 3,350 作为聚合物（沉淀剂）。 PEG 的浓度从 12% w/v 到 20% w/v 不等，这取决于与聚合物配对的缓冲液/盐的类型和浓度。 48 种 PEG/Ion 2 试剂中有 13 种含有单独的缓冲液成分。剩余的 PEG/Ion 2 试剂由滴定的有机酸盐缓冲。这 13 种条件中有 6 种采用新型柠檬酸 BIS-TRIS 丙烷 (CBTP) 缓冲液。 CBTP 缓冲液使用柠檬酸和 BIS-TRIS 丙烷作为酸碱对，创建一个双组分缓冲系统，在 pH 2.5 至 9.5 范围内有效。柠檬酸与 BIS-TRIS 丙烷的比例决定了溶液的 pH 值。四十八种PEG/Ion 2 试剂中的三十五种含有在聚合物存在下中和或pH调节的有机酸。中和的有机酸是高效结晶盐。1 四种 PEG/Ion 2 试剂具有多价阳离子。其中两种试剂含有阳离子混合物，通过仅用两种试剂筛选六种不同的阳离子来节省样品。胰蛋白胨，一种酪蛋白消化肽组合文库，包含在 PEG/Ion 2 中。PEG/Ion 2 试剂 1-30、42、45-47 在配制时不使用缓冲液，并且未进行 pH 滴定。

PEG/Ion 包含 48 种独特的试剂，每种试剂 10 ml。

PEG/Ion 2 包含 48 种独特的试剂，每种试剂 10 ml。

PEG/Ion HT 在单个 Deep Well 模块中包含 1 ml 来自 PEG/Ion 和 PEG/Ion 2 的每种试剂。

即用型试剂经过无菌过滤和超纯 1 类水配制，使用最高纯度的盐、聚合物、有机物和缓冲液。个别试剂可通过 Hampton Research Custom Shop 购买。

 

PEG/Ion Screen

PEG/Ion 2 Screen

PEG/Ion HT

 HR2-126 PEG/Ion Documents HR2-126 PEG/Ion SDS HR2-098 PEG/Ion 2 Documents HR2-098 PEG/Ion 2 SDS HR2-139 PEG/Ion HT Documents HR2-139 PEG/Ion HT SDS PEG/Ion Formulation & Scoring Data

1. Expression, purification, crystallization and preliminary X-ray diffraction analysis of Bifidobacterium adolescentis xylose isomerase. C. V. dos Reis, A. Bernardes and I. Polikarpov. Acta Cryst. (2013). F69, 588-591.

2. A comparison of salts for the crystallization of macromolecules. Alexander McPherson. Protein Science (2001), 10:418-422.

3. Searching for silver bullets: An alternative strategy for crystallizing macromolecules. Alexander McPherson and Bob Cudney. Journal of Structural Biology Volume 156, Issue 3 , December 2006, Pages 387-406.

4. Mechanisms for Glycolipid Antigen-Driven Cytokine Polarization by Valpha14i NKT Cells. Sulliivan et al, The Journal of Immunology, 2010, 184, 141 -153. (PEG/Ion 2)

5. Optimization of salt concentration in PEG-based crystallization solutions. Yamanaka M, Inaka K, Furubayashi N, Matsushima M, Takahashi S, Tanaka H, Sano S, Sato M, Kobayashi T, Tanaka T. J Synchrotron Radiat. 2011 Jan;18(1):84-7. doi: 10.1107/S0909049510035995. Epub 2010 Nov 5.

6. Crystallization and preliminary X-ray crystallographic analysis of importin-[alpha] from Neurospora crassa. N. E. Bernardes, A. A. S. Takeda, F. Z. Freitas, M. C. Bertolini and M. R. M. Fontes. Acta Cryst. (2014). F70, 501-504 [ doi:10.1107/S2053230X14005068 ]